Quick-adjusting plunger mechanism for blindstitch sewing machines



Aug. ll, 1925.

1,548,897 c; w. MUELLER QUICK ADJUSTING PLUNGER MECHANISM FOR -BLIINDS'I'ITCH SEWING MACHINES Filed Jan. '7, 1924 3 Sheets-Sheet 1 Aug. 1l, l 925.

' C. W. MU ELLER QUICK ADJUSTING PLUNGER MECHANISM FOR BLINDsTITcH SEWING MACHINES s sheets-sheet 2 Filed Jan. '7, 1924 graven to@ (MrZeH/zelkr 61H0: nu Lf Patented ug. 11, 1925.

:ig-1 "il CHARLES W. MUELLER,OF ST. LOUIS, MISSOURI, ASSIGNOR TO LEWIS INVISIBLE STITCH MACHINE CO., A CORPORATION OE MAINE.

QUICK-ADJUSTING PL'UNGER MECHANISM `IlOIl. BLINDSTITCH SEWING MACHINES.

Application led January 7, 1924. Serial No. 684,745.

To all whom it may concern.'

Be it known that Crim-inns W. MUELLER, a citizen of the United States, residing at St. Louis, State of Missouri, has invented certain new and useful Improvements in Quickilidjustingl Plunger Mechanism for Blindstiteh Sewing Machines, of which the following` is a specification.

This invention relates to new and useful in'iprovements in blind stitch sewing machines generally, although more particularly to the plunger mechanism thereof.

ln blind stitch operations it is very often desirable to vary the depth of the needle penetration, such as, when stitching over pockets, when going from one weight of fabric to another, or when going from an unironed fabric to an ironed fabric. Heretofore, in blind stitch sewing machines such as is shown and described in my copending application Ser. No. 692,696 filed February 14, 1924:, the bodily vertical position of reciprocation of the plunger is adjusted through the medium of an endwise movable sleeve which is normally clamped inthe frame. lt is necessary to first loosen this clamp before adjusting the sleeve in order to effect adjustment of the bodily vertical position of reciprocation of the plunger. rllliis mechanism is therefore slow and tedious and in cert-ain blind stitch operations, in order to obtain i'nairnum production, it is desirable to provide a mechanism whereby the bodily vertical position of reciprocation of the plunger may be quickly adjusted to suit the various working conditions.

lt is, therefore, one of the principal objects of my invention to providek an adjusting mechanism of the character described which .is capable of being rapidly adjustedr without having to first release' the clamp from the vadjusting sleeve.

Another object of the invention is to provide a plunger adjusting mechanism with meal whereby a predete mined adjustment within definite limits may be readily made and whereby the plunger mechanism may be readily returned to its initial position of a dj u stment. y

With the above and other object-s in view which will more readily appear as the nature of the invention is better understood, the same consists in the novel construction, coin'- bination and arrangement of parts hereinafchine.

Figure 3 is a detail top plan view of the plunger adjusting mechanism.

Figure 4 is a detail end elevation of the machine.

Figure 5 is an enlarged longitudinal sectional view showing the driving connections between the plunger and the cradle, and

Figure 6 is a detail 'view of the vertically movable pivot block for the feed mechanism.

Like reference numerals designate corresponding parts in all the figures of the drawings.

The sewing machine consistsv of a base 5 having at one end the work handling mechanism, a post 6 which 'extends upwardly from the other end thereof and an overhanging arm 7 which is supported by the post and carries at its outer or vfree end a stitching head 8, said stitching head being disposed above the work handling mechanism.

rlhis stitching head is of the type shown and described in my copending application mentioned above and it is, therefore, thought that a detail description thereof is unnecessary. rThe stitching head carries at itsy lower extremity a presser-foot 9 for coop-- eration with the stitch forming and work handling mechanisms.

The operating par-ts carried by the stitching head 8 and the work-handling mechanism carried by the base 5 are dri-ven from a main shaft l0 which extends longitudinally in the overhanging arm 7 and is suitably journaled therein, said shaft having a hand wheel pulley ll fixed to the right hand end thereof.

The work-handling mechanism which cooperates with the presser foot 9 includes a feed dog 12 and a work clamp 13. The feed dog is of the a-motion type, that is, it has a baclward and forward movement and an up and down movement. The backward and forward movement of the feed dog is obtained through a roel: shaft 14, and the up and down movement of the feed dog is obtained from a roel: shaft 15. These rock shafts 14 and 15 extend longitudinally within the base and have their right hand ends journaled in beari formed in a depending lug 15 and their leit hand ends journaled in bearings formed in a block 17 detachably secured to the left hand end of the base 5 by screws 13-13. Fixed to the outer end of the shaft 14 is a r el( arm 19 and pivotally connecting the outer end of the rock arm and the forward extremity of the feed dog 12 is a link 20. The roel; arm 19 extends in a general 1"ertical direction and the linlr 2O extends in a general horizontal direction, thus upon movement of the roch arm the link 2O will impart backward and forward movements to the feed dog 12. rlhe feed dog 12 is pivotally connected as at 21 to the upper end of a substantially vertically disposed linl; 22, the lower end of said link being pivotally connected as at 23 to the horizontal arm 24 of a bell crank lev r 25, the vertical arm 26 of said bell crank lever being pivotally connected as at 2'? to one end of a link 28, the other end of said linlt 2S being pivot-ally connected as at 29 to the outer end of a vertically disposed roch arm 30 fixed to the feed lift shaft 1.5. ln order to maintain the feed surface of the feed dog in a substantially horizontal plane during the feeding movements thereof, l provide spring 3l which is connected between a pin 32 on the link 22 and a pendant tail 33 fixed to the feed dog.

It will, therefore, be observed that upon rocking movement of 'the shaft 15 the vertical link 22 will le bodily raised and lowered and consequently the feed dog will be given its up and down movements. By proper timing of the shafts 14 and 15 a 4-way feed motion will be iinparted to the feed dog.

The bell crank lever 25 is )ivoted as :it 34, and this pivot is lifted to a head 35 cured te the lower end of a guide post 36, said head and post forming a vertically movn able carrier. rlhe post 36 is incnnted for vertical sliding movements in a bore formed in the block 17, and this block is formed with a seat 37 for receiving and limiting` the upward movement of the carrier. rThis carrier is normally held in its highest position by means of a flat spring 38 the inner end of which is rigidly secured to the base 5 and the free end thereof is disposed nnder the carrier so as to yieldably hold the latter in its highest position. The upper end of the post .iects above the block 17 and carries a pair of rearwardly extending` arms lieti-.veen which is pivoted as at 4G the work clamp 13. From the foregoing, it will be obserifed that when the carrier is moved Leases? downwardly against the tension of the spring 38, both the feed dog 12 and the work clamp 13 will be correspondingly moved, thus permitting the wei-l: presenting mechanism to be depressec a an entirety. lin order to so depress the work presentingl mechanism, l have provided an operating lever 41 which is fulcruined on the base and has one end disposed in contact with the upper face of the head 35. The other end of the lever is adapted to be raised through the application of a knee shifting device or treadle, neither of .vhich however shown in the drawings.

From the foregoing, it will be observed that when the feed dog is elevated to its highest position, the fulcrum of the bell crank lever is then shifted to the pivot 23 and consequently the last part of the rocking movement of the crank arm 30 will cause the bell crank 25 to be moved downwardly about its fulcrum 23 thus lowering the work clamp 13. The parts are so timed that the worl; clamp is thus lowered prior to the feeding movement of the feed dog. The reverse order of movement will take place substantially the time when the feed dog reaches the end of its feeding stroke, thus causing the clamp to engage the fabric and clamp the latter against the foot prior to the time the feed dog begins its downward movement.

In order to rock the shaft 14 and the shaft 15 I provide the main shaft 10 with eccentrics 42 and 43 respectively. A connection rod 44 has its upper end engageable with the eccentric 42 and its lower end pivotally connected as at 45 to a rock arm 46 fixed to the rock shaft 14. A connection rod 47 has its upper end engageable with the eccentric 43 and its lower end pivotally connected as at 43 to a roel: arm 49 lined to the shaft 15. lft will be noted that the connection rods and 4T are disposed within the post 6 of the machine frame.

The fabric as it is fed past the stitching head is adapted to be intermittently crimped or bent so as to form a node which will. be positioned in the path of the needle whereby the latter will, er will not, depending upon the height of the node, enter said node and project a penetrant needle thread loop therethrough, as will hereinafter be more fully described. In order to provide for this crimping or bending action of the material, the presser foot S) is formed with an opening 50. The material is upwardly bent or crimped into this opening by means of a reciprocatory plunger 51 which extends upwardly through the feed dog 12 and work clamp 13. This plunger is mounted for vertical sliding movements within a barrel fitted within a bore 53 formed in the end block 17. The lower end of the plunger 51 is formed with a reduced end 54 forming a loo resultant shoulder 55. The lower end of the barrel 52 is fixed to a lug 56 and the reduced end 54 of the plunger' extends freely through an opening 57 formed in said lug and threaded onto the lower projecting end thereof are lock nuts 58. Disposed within the barrel 52 between the shoulder 55 of the plunger and the lug'56 is a coil spring 59 which yieldably holds the plunger in its highest position relative to the lug 56. It will be evident that when the barrel is moved upwardly the plunger will be m'ovet therewith, but just as soon as the plunger engages the fabric a resistance to the upward movement of said plunger will take place and the spring 59 will permit the barrel to continue its movement while the plunger spring 59 is being compressed.

The plunger 51 is vertically reciprocated through the medium of a rock shaft 60 which extends longitudinally of the base 5. The rock shaft 60 is provided with a crank arm 61 which is connected by a link 62 to the lug 56. The rock shaft 60 is located below the plunger and the link 62 extends substantially vertically when the plunger is at its highest position.

For the purpose of bodily varying the vertical position of reciprocation of the plunger, I have supported the rock shaft 60 for vertical bodily movements and have journaled the shaft in bearings formed in a cradle or rocking frame which I have designated as a whole by the reference numeral 63. This cradle includes a rock shaft 64 having one end supported for rocking movements on pins 65-65 respectively vcarried by the end wall of the base 5 and the depending lug 16 of said base. The rockshaft 64 is provided with downwardly and rearwardly extending rock arms 66-66 in which the plunger rock shaft 60 isjournaled. The rock shaft 64 of the cradle is provided adjacent its right end with a laterally and longitudinally extending rock arm 67 having forwardly extending arms 68-68. Disposed between the arms 68-68 is a sleeve 69 forming a slide bearing for the lower end of a vertically disposed cam roller shaft 70. The sleeve 69 is supported en the arms 68- 68 by horizontally disposed pivot pins 71-` 71. Fixed to the sleeve 69 is a face cam 72 and this cam is formed on its upper face,

with a curved surface containing diametrically opposed high points 7873 and diametrically opposed low points 7 4 7 4. The cam roller shaft 70 extends upwardly through the post 6 of the framey and is driven from the main shaft 10 by a gear coupling' 75 which reduces the speed of rotation of the cam roller shaft 70 relative to the main shaft 10 by the ratio 1 ,to 4. This gear couplings-7 5 includes a spiral gear which is fixed tov the cam roller shaftY 70 through the medium l" of a collari75.b and a spiral gear 7 5c which is fixed to the main shaft 10. The cam roller shaft extends through a concentric opening 1n the cam 7 2 and fixed to the shaft directly above the cam face of said cam is a sleeve 7 which carries a cam roller 77 engageable with the cam face of the cam. The upper end of the cam roller shaft 70 above the gear coupling 75 is mounted within a sleeve 78 which has threaded'engagement with an opening formed in a plate 79 which is detachably secured to the upper end of the frame. The lowerl end of the sleeve rests on the collar y75b of the gear coupling. Fixed to the upper end of the sleeve 78 is a laterally extending hand lever 8O by means of which the sleeve may be turned and the vertical position thereof consequently adjusted. the upper end of the cam roller shaft 70 and the head of this screw bears against the upper end of the sleeve 78. Thus, the cam roller shaft 70 is held against longitudinal movement relative to the sleeve 78 by means of the gear collar 75b and the screw 76s.

The plunger shaft 60 is rocked in the supporting cradle or frame 68 by the rock arm 49, the outer end of which is pivotally connected as at 49a, the lower end of the link being pivotally connected as at 49C to a rock arm 60n fixed to the plunger shaft 60. Inasmuch as the cam 72 is provided with two high points and two low points,.and the main shaft makes four complete revolutions to one of the cam roller shaft 70, it follows that the bodily position of reciprocation of the plunger will be elevated during every other revolution of the main shaft.

By turning the hand lever 8O in a clockwise direction, the sleeve 78 will be moved downwardly, and through the medium of the gear collar 7 5b the cam roller shaft 70 will be moved downwardly for a corresponding distance. This downward movement of the cam roller shaft through the medium of the roller 77 causes the cradle 63 to be rocked, thus elevating the plunger shaft 60, the latter being moved upwardly in an arc about the pivot of the cradle. The upward bodily movement of the shaft 60 will in turn bodily elevate the position of reciprocation of the plunger 51 through the medium of the rock arm 61, link 62 and lug 56.

By turning the hand lever 80 in an anticlockwise direction, the cam roller shaft 70 will be elevated and the plunger rock shaft 60 will be lowered, thus lowering the bodily position of reciprocation of the plunger 51.

In order to lock the sleeve 78 in a predetermined position of adjustment, and yet permit of a rapid release and new adjustment, I have provided the hand lever 8O with a releasable latch which cooperates with the plate 79. This latch comprises an upwardly extending housing 81 which is A screw 70a is threaded into fixed to and is located at the outer end of the hand lever 80. This housing has a closed upper end and an open lower end. Disposed within the housing is a vertically movable latch-pin S2, the upper end thereof projecting through an opening formed in the upper end of the housing and having a linger piece or head 83 fixed thereon, the lower end of said latch-pin projecting below said housing for engagement in any one of a plurality of seats 84- which are formed in the plate 79f These seats are spaced apart and are disposed in a circle which is concentric to the sleeve 7S. Fixed to the lower portion of the latch-pin 82 is a shoulder 85, and disposed around the pin between the upper end of the housing and said shoulder is a coil spring 86 which normally urges the latch-pin downwardly.

Thus, after the plunger mechanism has been set, and the operator desires to effect a quick adjustment of the plunger, either up or down, it is only necessary to raise the latch-pin against the tension of the spring 86 and then while holding the latch-pin in its raised position, swing the hand lever in the desired direction for required distance, and then release the pin whereupon the latter will automatically seat itself in the registering seat 84. The operator, by counting the number of seats intervening between the seat of original setting and the seat of adjustment, may readily return the parts to their original setting.

A quick adjustment of the plunger mechh anism is often desired, such as during the operation of felling the facings to coats in order to avoid sewing down the inside pockets. In this operation, it is necessary to lower the bodily position of reoiprocation of the plunger so as to insure the needle penetrating only the upper ply of material, or when going from an unironed garment to an ironed garment it is necessary to raise the bodily position of reciprocation of the plunger in order for the needle to penetrate said unironed garment, or when going from a garment of one weight to a garment of another weight.

I claim:

l. In a blind-stitch sewing machine, the combination with a presser-foot, of a vertically reciprocatory plunger therebelow, a main shaft, means connected with said shaft for reciprocating said plunger, and means for quickly adjusting the vertical bodily position of reciprocation of said plunger, said adjusting means including an endwise movable cam roller shaft, means for rotating said cam roller shaft from said main shaft, and means connected to said cam roller shaft including a lever-handle for moving the cam roller shaft endwise to adjust the vertical bodily position of reciprocation of said plunger.

2. In a blind-stitch sewing machine, the combination with a presser-foot, of a vertically reciprocatory plunger therebelow, a main shaft, means connected with said shaft for reciprocating said plunger, and means for quickly adjusting the vertical bodily position of reciprocation of said plunger, said adjusting means including a rocking-frame, a cam carried by said frame, an endwise movable cam roller shaft, a roller on said shaft cooperating with said cam for oscillating said frame, means for rotating said cam roller shaft from said main shaft, and means connected to said cam roller shaft including a lever-handle for moving the cam roller shaft endwise to adjust the vertical bodily position of reciprocation of said plunger.

3. In a blind-stitch sewingmachine, the combination with a main frame, of a presserfoot connected thereto, a vertically reciprocatory plunger therebelow, means for reciprocating said plunger, and means for quickly adjusting the vertical bodily position of reciprocation of said plunger including an endwise movable cam roller shaft, a sleeve surrounding said cam roller shaft and having threaded engagement with said main frame, said sleeve engaging the shaft to move the shaft endwise upon rotation of the sleeve, and a lever arm fixed to the sleeve for rotating the latter.

4. ln a blind-stitch sewing machine, the combination with a main frame, of a presserfoot connected thereto, a vertically reciprocatory plunger therebelow, means for reciprocating said plunger, and means for quickly adjusting the vertical bodily position of reciprocation of said plunger including an endwise movable cam roller shaft, a sleeve surrounding said cam roller shaft and having threaded engagement with said main frame, said sleeve engaging the shaft to move the shaft endwise upon rotation of the sleeve, a lever arm fixed to the sleeve for rotating the latter, and cooperating means between the lever-handle and the main frame to lock the former in a predetermined position of adjustment.

5. In a blind-stitch sewing machine, the combination with a main frame, of apresserfoot connected thereto, a vertically reciprocatory plunger therebelow, means for reciprocating said plunger, and means for quickly adjusting the vertical bodily position of reoiprocation of said plunger including an endwise movable cam roller shaft, a sleeve surrounding said cam roller shaft and having threaded engagement with said main frame, said sleeve engaging the shaft to move the shaft endwise upon rotation of the sleeve, a lever-handle for quickly rotating the sleeve, said frame being provided with a plurality of spaced seats arranged in concentric line about the sleeve, and readily releasable means carried by the lever-handle for engagement with any one of said seats.

6. In a blind-stitch sevving machine, the combination With a main frame, of a presser- `foot connected thereto, a vertically reciprocatory plunger therebelow, means for reciprocating said plunger, and means for quickly adjusting the vertical bodily position of reciprocation of said plunger including an endwise movable cam roller shaft, a sleeve surrounding said cam roller shaft and having threaded engagement With said main frame, said sleeve engaging the shaft to move the shaft endWise upon rotation of the sleeve, a lever-handle for quickly rotating the sleeve, said frame being provided With a plurality of spaced seats arranged in a concentric line about the sleeve, and a spring actuated latch carried by the lever handle for engagement With any one of said seats.

7. In a blind-stitch sewing machine, the combination With a main frame, of a presserfoot connected thereto, a vertically reciprocatory plunger therebelovv, means for reciprocating said plunger, and means for quickly adjusting the vertical bodily position of reciprocation of said plunger including an endwise movable cam roller shaft, a sleeve surrounding said cam roller shaft and having threaded engagement With said main frame, said sleeve engaging the shaft to move the shaft endwise upon rotation of the sleeve, a lever-handle for quickly rotating the sleeve, said frame being provided With a plurality of spaced seats arranged in a concentric line about the sleeve, a vertically movable latch mounted in said lever-handle and engageable With any one of said seats, a spring carried by said leverhandle for normally urging said latch dovvn- Wardly into engagement with a predetermined seat, and a head carried by said latch tor elevating the latter from engagement with the predetermined seat.4

In testimony whereof I hereunto aPX my signature in the presence of tWo Witnesses.

CHARLES W. MUELLER.

Vitnesses z C. L. NUESINER, J. H. ANDERSON. 

